We've been using TypeScript for 9 months now on a large project. It's fantastic. There's now way I'll go back to pure JavaScript again. The type system just catches so many defects, and they're of the kind that are hard and boring to find (typos). Plus IntelliSense integration (including jsdoc) is great. On the downside, our project takes some time to compile so we had to build a tool to do it incrementally. Plus it…
Agreed, TypeScript is great, but the compiler is excruciatingly slow. I have to segment my app into multiple sub-build areas and only build a subset at a time, which is annoying because I frequently end up making small changes outside of that subset of code. My app is only around 25000 lines of code and a full compilation still takes around 50-60 seconds which, in a JavaScript workflow, is a lot of friction.
interface Person {
firstname: string;
lastname: string;
}
function greeter(person: Person) {
return 'Hello, ' + person.firstname + ' ' + person.lastname;
}
var user = {firstname: 'John', lastname: 'Doe'}
document.body.innerHTML = greeter(user);